Telephone system



Jan. 6. 1925.

G. R. EATON TELEPHONE SYSTEM Filed March so, 1922 Fatented 7 Jan. 6, 1925..

UhlilTEB STATES enses rarest @FFHCE' GEORGE R. EATON, or can Penn, ILLINOIS, nssrenon T0 KELLOGG swI'rcr-IBoAnn AND sUrrLY coMrA-NY, or 'crrioneo, ILLINOIS, A oonronarronor ILLINOIS.

TELEPHONE SYSTEM.

Application filed March 30, 1922. Serial No. 548,016.

To all whom it may concern:

Be it known that I, GEORGE R. EATON, a citizen of the United States of America,and a resident of Oak Park, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification. 7

My invention relates to telephone systems in which link circuits are provided for interconnecting telephone lines as calling and called lines, and one feature has to do more particularly with the provision of an operators link circuit which has link disconnect means at its answering end and at its calling end for disassociating the link circuit from the calling subscribers line and called subscribers line, whereby either subscriber may initiate a new call or be called, as the case may be, prior to the disconnection of the link circuit terminals from the jack terminals of the said telephone lines.

A feature of my invention relates to improved means for placing the link disconnect meansin the answering end of the link circuit under the control otthe calling jsub scriber and the link disconnect means in the calling end of the link circuit under the sole control of the callingsubscriber only when the calling end of the link circuit is connected to a circuit having a low resistance cutoff relay, as, for instance, a trunk line, but when said calling end is connected to a line circuit having a high resistance cut-oil relay, as, for instanc e, a local line, the callingend link disconnect means is under control of both the calling and called subscribers. In, order to place the calling end link disconnect means under the control of the calling subscriber in one instance, and under the control of both calling and called subscribers in the second instance, I provide arelay in the link circuit which is operable when the link circuit is connected to a trunk line to place the said disconnect means under the sole control or the calling subscriber, but when the link circuit is connected to a local line, the said relay does not operate due to the high resistance of the cut-ofi' relay in the line circuit of the local line, whereby the said relay failing to operate, the said link disconnect means is under the control of the calling and called subscriber.

Another feature of my invention is the provision of a meter service device in the line circuit of a calling subscribers line and means in the link circuit'operable to operate said meter servicedevice, whereby the call between a calling and a called subscriber is registered only when the called subscriber responds to operate said linkmeans.- This feature is further characterized by the fact that means are also provided for preventing the registration of more than one completed call between the same subscribers lines upon the same interconnection of said subscribers lines. V

The above features, as well as others not specifically pointed out above, will be more fully and particularly pointed out in the ensuing specification, reference being had to the accompanying drawings which show my invention diagrammatically and in which:

Fig. 1 shows the link circuit of my invention and a calling and called sub-station terminating in multiple jacks of a .line circuit, respectively; and

FigLQ shows the outgoing end of a trunk circuit having a low resistance cut-off relay associated therewith.

Referring now more in general to my invention as illustrated in Fig. lot the drawings, it comprises a calling substation A connected at the exchange with a wellknown line circuit L, comprising multiple answering jacks J, cut-ofi relay 00, line relay LR, multiple line lamps S, a call regiss tering device RW, and its associated line service meter relay LSM. To the right of the drawing, I show a called substation B connected to a line circuit L, having the usual line relay LR, cut-off relay CO, multiple line lamps S, multiple call registering device BIN, jacks J, and line service meter LSM. The line circuits L and L shown are provided with multiple line lamps S and answering jacks J so thataejack and signal S appear in a plurality of operators positions. When a call is initiated a lighted line signal S appears before each jack J, and any one of aeplurality of operators may answer the call to the exclusion of the others.

The cord circuit C illustrated in the drawing is arranged for interconnecting the telephone lines A and B and comprises an answering plug AP and a calling plug CF interconnected by the heavily marked talking conductors with the condensers G interposed. The answering end of the cord circuit C comprises an answering supervisory relay AS for the usual supervisory purposes controlling the answering supervisory lamp AL, and the cord C is also provided with a sleeve relay SL for the purpose of preventing more than one operator from seizing the call, as well as for other purposes which will be hereinafter described. An operators listening relay LS is provided which, when operated, connects the operators set 0 to the talking conductors of the cord C. A call answering meter device CAM for registering each call answered by the operator is also shown. A link disconnect relay Ll) is energized when the subscriber at the calling substation replaces his receiver upon the switchhook to dissociate the cord circuit from line circuit L, giving the subscriber instantaneous recall facilities.

The calling end of the cord circuit C comprises a calling sleeve relay SE and a calling supervisory relay CS serving the usual supervisory purposes and for controlling the calling supervisory lamp CL A ringing control relay RC is also pro vided which is energized when any one of the ringing key plungers oi? the party-line ringing key BK is depressed to connect interrupter relay IR in cir uit with the interrupter 1, whereby ringing current is intermittently applied to the called telephone line B. A ringing trip relay ET is provided for disconnecting ringing current from the called line should the called subscriber remove his receiver duringa ringing period, the ringing current being disconnected by the supervisory relay CS should the called subscriber respond during a silent period. The calling end of the cord C is also provided with a link disconnect relay Ll) and an auxiliary sleeve relay ASL. When the lug CP is inserted into a jack J, relay D energizes but relay ASL will not energize due to the high resistance of the cut-oil relay CO. Relay ASL failing to energize places the link disconnect means under the joint control of the calling and called subscribers, so that it is necessary for both subseribers to replace their receivers before the calling end of the link circuit is disassociated from the line circuit L. Should the plug OP be connected to a jack other than jack J, as for example a trunk line having a low resistance cut-cit relay, relays Ll) and ASL will energize in series and will place the link disconnect means LD under the control of the calling subscriber to the exclusion of the called subscriber, so as to give the local operator a disconnect signal as soon as the calling subscriber replaces his receiver so that the apparatus 1s ava1l able for establishing other connections, thereby making it unnecessary for the called subscriber to replace his receiver to efiect a disassocia-tion of the cord circuit C from the trunk circuit having a low resistance cutoii relay. By this arrangement, the trunk line may be immediately freed from the cord C upon the replacing of the calling subscribers receiver upon its switchhook.

I also show a meter relay Mid, which energizes when the relay CS operates upon the response o1 the called subscriber to connect battery to the line meter relay LSM in the line circuit L to cause the same to operate and register the completed call. A relay D is also provided for opening the circuit of the meter relay MR after the meter relay MP.- is energized and also for closing a locking circuit for itself and circuit for the calling supervisory lamp CL. Thus, it will be understood that it is impossible to register more than one call so long as the plug GP remains in the calling jack J.

Referring to Fig. 2 in general, a trunk circuit T is illustrated which comprises a pair of conductors 100 and 101 extending from a distant exchange and terminating in multiple trunk jacks TJ at the exchange where the cord circuit C is located. A trunk signal TS is also provided which has a relay TLR associated therewith for controlling the same. A. low resistance cut-oil relay CO is also provided for controlling the re lay TLR and is of such resistance to permit the relay ASL in the cord circuit (l to energize when the plug GP is inserted into the trunk jack TJ, said relays CO and ASL energizing in series. Cut-oh relay (1G of the trunk circuit T will not, however, due to the high resistance winding of said relay SR.

Having described in general the apparatus employed in a preferred embodiment o't my invention, I will now describe more in detail the operation of the system as illus-- trated in Fig. 1.

Assuming that the substation A initiates a call, the removal of the receiver thcreat establishes an energizing circuit for the line relay LR of the line circuit L, traced from battery, winding of relay LR, normal contact 1 of cut-oil relay CO, through the closed switchhook contacts of substation A, normal contact 2 or cut-oil relay C9 to ground. Line relay Lit-energizing closes its normally open contact 3, whereby circuit is closed for the line signals S which light at the different associated jacks J, each ack J appearing at a different operators position. The first operator to seize the call by the insertion of her answering plug AP .into the jack J before which the signal S is lighted, closes an energizing circuit for the sleeve lay SL, traced from battery, through both its windings, conductors i and 5, normal contact 6 of relay LD, conductor 7, sleeve contacts of the plug AP and ack J, winding of cut-oil relay CO, both windings of meter service relay LSM, to ground. Relays SL and CO energize in series, but the upper winding oi relay LSM being of high resistance, relay LSM will not operate over this circuit. Relay SR energizing closes its alternate contact 8 to shunt out its upper high resistance winding and is then held energized over the remaining part of the circuit just traced. The energization of cutoil relay CC opens normally closed contacts 1 and 2 to permit line relay LR to restore to normal whereby its alternate contact 3 is opened to cause the eftacement of the line signals S. A further operation due to the energization of sleeve relay SL is the operation of answering supervisory relay AS over a circuit from battery, through its lower winding, normal contact 9 of relay LD, ring contacts of the plug AP and jack J, through the substation A, tip contacts of the jack J and plug AP, normal contact 10 of relay LD, conductor 11, alternate contact 12 of relay SL, upper winding of relay AS to ground. Relay AS energizing opens its normal contact 13 to prevent the premature lighting of the lamp AL and the operation of link disconnect relay LD, and also closes its alternate contact 13 to cause the operation of the call answering meter device CAM to register the call answered by the operator, over a circuit traced from battery, winding of the relay CAM, alternate contact 13 of relay AS to ground at normal contact 47 of relay Ll). Another result due to the energization of I relay SL is the energization of the operators listening relay LS, traced from battery, through the winding of relay LS, alternate contact 14 of relay SL, conductor 15, normal contact 16 of the calling sleeve relay SR to ground. Listening relay LS energizing closes its alternate contacts 17, 18 to connect the operators head set C to the cord circuit C, whereupon the operator inquires the wants of the calling subscriber A.

The feature whereby all the operators who attemptto seize the call subsequently to the seizure of the call by the first operator, are excluded, will now be explained. When the first operator to seize the call inserted her answering plug AP into the jack J, the sleeve relay SL in her cord circuit operated over a circuit extended through its lower low resistanre winding and its upper high resistance winding, and the energization of relay SL brings about the operation of relay LS to connect the operators set C in conversational circuit with the calling substa tion A. Upon the energizat-ion of relay SL it closes its alternate contact 8, thus shunting out its high resistance winding and remains energized through its low resistance winding only. When an operator inserts her answering plug AP into a jack J subsequently to the insertion of the plug Al into the jack J, by the first operator, the sleeve relay SL in the second operators cord circuit will not operate, due to the low resistance path of relay SL of the first cord circuit; and, therefore. sufficient current Will not flow through the low or high resistance windings of the sleeve relay S in the second operators cord circuit to operate the same. The failure or" relay SL in the second cord circuit to operate prevents the listening relay associated therewith to energize to connect the second operators set to the calling line. The operator receiving no reply to her inquiry will know that the call has been seized by another operator, and will then withdraw her answering plug from the multiple jack J.

Referring now back to when the operator inquired the Wants of the calling subscriber A, and assuming that the subscriber A desires to converse with substation B, the operator will test the jack J to determine its idle or busy condition in the usual and Well known manner. Assuming the called line is idle, the operator will insert the calling plug CP into the jack J. The insertion of the calling plug CP into the jack J brings about the energization of the sleeve relay SR over a circuit traced from battery, winding of relay SR, sleeve contacts of plug CP and jack J, winding of cut-oil relay CO to ground. Cut-oil relay CC energizing takes the line relay LR and line lamps S out of the control of the called substation B. Relay SR energizing closes its alternate contact 16, thus opening the circuit of the listening relay LS to cause the same to restore and disconnect the operators set 0 from the cord circuit to provide secret service. Another result due to the insertion of the plug CP into the jackJ is the operation of the link disconnect relay LE to extend the talking conductors to the called line, the circuit being traced from battery,

Winding of relay Ll), conductor 21, normal contact 22 of relay Ll), conductor 23, winding of relay ASL, sleeve contacts of plug Cl? and jack J to ground through the winding of cut-oil relay CC of line circuit L. Relay ASL does not energize over this. circuit due to the high resistance of the winding of cut-oil relay CO. Relay ASL failing to operate, a circuit is closed for the supervisory lamp CL which lights and remains burning until the operator depresses one of the ringing key plungers or the ringing key RK to cause the operation of ring ing control relay RC to open the circuit of lamp CL to provide a dark keyshelt. The circuit for lamp CL may be traced from battery, through lamp CL, normal contact 24 of relay ASL, normal contact 36 of relay RC, conductor 27, normal contact 28 of re- V lay Ll), conductor 29, normal contact of relay RT, normal contact 31 of relay CS, conductor 32, to ground at alternate contact 16 of relay SP. Relays Ll) and ASL are in this instance under the control o1 the calling subscriber, but when the called sub scriber responds the relay Ll) is under the joint control or the calling and called subscriber. In case the plug CP is inserted into jack other than the jack J such as one of the trunk jacks Til Fig. 2), which has a low resistance cut-off relay rewith relay l TV under to the will be the control exclusion oi th called more fully her eina The plug C" the jack J and Lilli having been inserted into the relays Ll) and SE op erating, the operator will now depress one of the ringing liey plungers ot the ringing key Rh: to connect ringing current of the proper frequency to the called liner and assuniing generator G to be the equency required to signal substation B, ringing key plunger (3 will be fully depressed, inonientarily closing the end spring contacts so and 38 of the ringing key BK, closing an energizing circuit for the ringing control relay RC, traced from batter winding of relay BC, the now closed contact 26 of the end springs, conductor 27, normal contact 28, conductor 29, contact 01"" ringing trip relay RT, nornial contact 31 of relay CS, conductor 32, alternate contact 16 of relay SP to ground. ll-elay RC energizing closes its alternate contacts 33, 34, 35 and 36, thereby closing a locking circuit for itself through its alternate contact 36 independent -ot the end spring contact 26, and over the previously traced circuit. A circuit for the inter; pter relay R is also established from battery, lower winding of relay lllt, conductor 37, now closed contact 38 of the end springs, alternate contact of relay BC to ground. Belay lld; energizing connects ringing current to the called line, instantly upon the depression of a key plunger and upon the operation of relay RC, even though a dead segment oi the interrupter l is in circuit with relay lit, thus giv ng an instantaneous first ring. ll hen, however, the key plunger is restored to its intermediate position'rroin its fully depressed position, contacts 26 and 38 are opened but an interrupter l is connected in circuit with interrupter relay Ht due to the ener 'iZ-ation of relay BC, over a circuit traced from battery, upper winding 01 relay Ilt, conductor 39, alternate contact 34 of relay R6 to ground, through the constantly rotating interrupter 1. Relay IR is thus intermittently energized and deenergized over the last traced circuit to intermittently connect ringing current to the called line. The ringing cur menace rent may be traced from generator G, alternate contact of key plunger 6, which remains closed until another lrey is depressed, lower winding of relay RT, alternate contact 4:0 of relay IR, tip contacts of plug and jack 5, through the bell and condenser of substation B, ring contacts of jack 5" and plug GP, alternate contact of relay ill to battery and ground. Relay lt'l will not energize over this circuit due to the high res stanceof the hell and condenser at substation ll. During each time ri ging current applied to the called line, the calling subscriber A will receive a reyertive tone which will notify him that the called subscriber ll is being signaled, this revertiyc tone. being given over a circuit traced from generator G resistance and concenser C, alternate contact ll of relay IR, conducter 44, alternate contact 33 of relay RC, tip conductor or cord circuit C, norinal contact 10 of relay Ll), tip contacts of plug Al. and jack J, through receiver and condenser at substation A, ring contacts of jack J and plug Al ring conductor of cord C, normal contact 9 of relay LD, to battery through the lower Winding of relay AS. The call bell at substation B will be intermittently signaled until the subscriber thereat removes his receiver from the switchhoolr, whereupon ringing current will be autoniatically disconnected from the called line during either a ringing period or non-ringing period. Assun'iing the subscriber ll responds during a ringing period, ringing trip relay ll'l will be energized now due to the bell and condenser being disconnected by the closure of the switchhook contacts which permits suthcient current to flow to energize said relay RT, and the relay RT energizing opens its normal contact 30, thereby opening the circuit of ringing control relay RC, which deenergizes and opens the circuit of the interrupter relay ER, with interrupter l at 34 to preventthe further operation of relay IR and the application of ringing current to the called line. Should subscriber B respond during a non-ringing period, calling supervisory relay CS will be energized over a circuit traced from battery, lower wind ng of relay CS, ring conductor oi? cord C, alternate contact d6 of relay Ll), normal contact 43 of relay IR, ring contacts of plug GP and jack J through the now closed switchhook contacts of substation B, tip contacts of jack J and plug GP, normal contact 40 of relay llt, alternate contact 47 of relay LD, conductor 48, through the upper winding of relay CS, to ground at alternate contact 4L8 of relay Ll). Relay CS operating opens the looking circuit of relay RC at 31, whereupon relay RC restores and opens the circuit of relay IR as hereinbe'fore described. Ringing control relay RC restoring closes its normal contacts and 33, relay 11% its contacts 40 and 43, thus closing the continuity of the talking conductors and connecting subscribers A and B in conversational circuit.

Should the calling subscriber A hang up his receiver before subscriber B removes his receiver, ringing current will be automatically disconnected from the called line, due to the energization of relay LD over a circuit traced from battery, winding of relay LD, normal contact 13 of relay AS, which de-energizes when the switchhook contacts at substation A are opened, alternate contact 45 of sleeve relay SL, to ground at alternate contact 16 of relay SR, Link disconnect relay LD energizing opens the locking circuit of ringing control relay RC at normally closed contact 28, and relay RC de-energizing, the circuit of interrupter relay IR is opened at alternate contact 34, thereby preventing further application of ringing current to the called line.

I will now describe the operation of the meter service registering apparatus. When the called subscriber B responded and the calling supervisory relay CS operated, a circuit was closed for the slow-to-release meter relay MR, traced from battery, through the winding of relay MR, normal contact 51 of relay D, alternate cont-act 31 of relay CS, conductor 32, to ground at alternate contact 16 of relay SR. Relay MR energizing closes an energizing circuit for the line service meter relay LSM of line switch L from battery, alternate contact 53, conductor 55, conductor 5, normal contact 6 of relay LD, sleeve contacts of plug AP and jack J, winding of cut-off relay CO, Winding of relay LSM to ground. Suihcient battery flows over this circuit to energize relay LSM, which attracts its armature to cause the pawl and armature to rotate the call registering Wheel R11 one step to register the call. Relay LSM operating closes its alternate contact 54, thereby closing a locking circuit for itself through its lower winding to ground at its alternate contact 54', thus shunting out its upper winding. Upon the energization of relay LMR and the shunting of its upper high resistance winding, relay LMR will remain energized in series with relays SR and CO over the circuit hereinbefore traced.

Meter relay MR operating closes an energizing circuit for relay D, which operates and the opening of its normal contact 51 opens the circuit of meter relay MR, the energizing circuit for relay D being traced from battery through the upper winding of relay D,nlternate contact 52 of relay MB to ground. The relay D has its initial energizing circuit opened at contact 52 upon the de-energization ofrelay MR, but a locking circuit is established for it traced from battery, through its lower winding, its alternate contact 50, conductor 32 to ground at alternate contact 16 of relay SR. Relay D is quick-acting and energizes immediately upon the energization of relay MB to open its normal contacts 51, thus opening the energizing circuit of relay MR, but relay MR being slow-acting remains operated sufficiently long to permit the operation of the line service meter relay LMR to register the call. Relay D remains energized as long as plug UP is connected to the jack J. Thus, it will be seen that the line service meter apparatus in the line circuit L can only operate to register one call, due to the circuit of relay MR being maintained opened at contact 51 of relay D,

The subscribers A and B are now in conversational circuit and upon termination of conversation they replace their respective receivers upon-their switchhooks. When the subscriber A replaces his receiver upon its switchhook, the energizing circuit for supervisory relay AS is opened at the switchhook contact, whereby relay AS restores to normal and closes a circuit for the link disconnect relay-LD, whereby the cord circuit is dis associated from the calling line and the calling subscriber is free to call or be calledeven though the plug AP of the cord circuit C remains in the jack J; the circuit for relay LD may be traced from battery through the winding of relay LD, normal contact 13 of relay AS, alternate contact 45 of relay SL, conductor 32, alternate contact 16 of relay SE to ground. Relay SL does not de-energize when relay LD operates but is maintained energized over a substitute circuit traced from battery through its lower winding alternate contact 8 of relay SL, conductors 4 and 5, alternate contact 6 of relay LD, which closes before relay SL has an opportunity to deenergize, alternate contact 45 of relay SL, conductor 32, to ground at alternate contact 16 of relay SR. When. relay LD energized, the energizing circuit for link disconnect relay LD was opened at contact 22 of relay LD, causing relay LD to restore to normal, if thercalled subscriber has replaced his receiver, it being remembered that relay ASL is not energized during this connection. The relay LD operating, its normal contacts 9 and 10 are opened, disassociating the cord circuit C from the line circuit L, thereby making it possible for subscriber A to initiate another call or be called, as the case may be, prior to the withdrawal of the plug AP from the jack J. The disconnection of the cord C and associated therewith to engage the next tooth ot the register wheel Rl V to be prepared to register the next call.

IWhen the called subscriber replaces his receiver, relay CS de-energizes to open the locking circuit of link disconnect relay Ll) at alternate contact 31 of relay CS, relay LI) will. not, however, de-energize if the calling subscriber has not replaced his re ceiver, as relay Ll) will not have operated and the primary energizing circuit of relay Ll) as hereinbefore traced will remain closed to prevent the de-energization of relay Ll), but if relay Ll) has operated, both energizing circuits for relay Ll) will be opened and relay Ll) will tie-energize to disasseciate the link circuit from called line circuit L. Relay CO, although in circuit with relay SR will not remain ope "at-ed since battery at relay Ll) is not now in circuitwith relay Ci) and sufficient current will not flow from battery through relay SE to maintain relay CO energized. Relay CO deenergizing replaces the line circuit L under the control of the subscriber B. The subscribers having replaced their receivers, the supervisory lamps AL and CL are lighted. The answering supervisory lamp AL is new lighted over a circuit traced tron battery, through the lamp AL, normal contact 12 of relay AS, alternate contact 45 of relay SE. to ground at alternate contact 16 of relay Sit, and the calling supervisory lamp CL is lighted over over a circuit traced from battery through the lamp CL. normal contact 24: of relay ASL, conductor 58 alternate contact- 28 of relay Ll), conductor 29. contact 30 of relay RT, normal contact 31 of relay Cid, conductor 32, to ground at contact 16 of relay SR. The operator observing the two lighted lamps AL and CL, will know the conversation has terminated. and will withdraw the plugs AP and GP from their respective jacks, thereby causing the apparatus to restore to normal in the well-known manner. Since the resistance of the cutoff relay CO is such that it does not remain energized when relay SR is only in se...' .o with it and relay LD is not in series circuit with cut-oil relay CO, the called subscriber-s line circuit L is free, and subscriber i may initiate acall or be called.

Assuming now that the plug CP is inserted into one of the trunk iaclrs T3 having the low resistance cut-ofi relay CO associ ated therewith, relay SR will energize v a through sa1d cut-0d relay CO and relays ASL and Ll) will energize in series with the low resistance cut-off relay CO or the trunk line T. This circuit niay be traced 'frombattery, through the winding of relay Ll) conductor 21, normal contact 22 of re lay Ll), conductor 23', winding of relay ASL, sleeve contacts. of plug ()P and jack; TJ of the trunk circuit T to ground through thelow resistance winding of the cutoff re CO Relay ASL energizes over this cireuu: and opens its contacts 24: and 25, and in this case the lamp CL does not burn prior to the depression of the ring key, as was the c when the plug GP was inserted into the ja J. The cut-oil relay CO energizing ov this circuit opens the circuit of relay 1 .1 to prevent relay TLB and signal TS from operating. The rest of the operation. in establishing the connection is the same hereinbetore described up to and until the calling party replaces his receiver. ASL and LD are under the sole control of the link disconnect relay DL associated w "h the calling end of the cord C at its contact 2:2, and when the calling subscriber replaces his receiver, line relay Ll) is energized he- ;tor described and the opening of normal contact 22 of relay Ll) allows relays L and ASL to restore, and as sleeve relay Ell; is now the only relay connected to the sleeve of the calling plug GP the cut-oft relay of the trunk restores due to the high resistance of relay SR and permits the trunl; circuit apparatus to restore so as to make it immediately available 'for use in establishing other connections. The response oi? the called party operates the meter LSM in the manner before described. in this instance relay ASL energizes and the opening or" ts normal contact 25 places the control of the relay LD under the control of the calling subscriber, it being remembered that in t 1e previous description the relay Ll) oi? t calling end of the cord C was placed in 100 ing circuit through alternate contact 31 relay CS and both subscribers A. and i. would have had to replace their receivers upon their respective switchhooks to bring about the de-energization of relay Ll). The calling subscriber having replaced his receiver, relay LD has energized and LD has de-energized, the answering supervisory lamp is lighted over the previous circuit and supervisory lamp CL will light over a circuit traced from battery through lamps CL, conductor 60, alternate contact 49 conductor 61, conductor 58, alternate contact 28 of relay Ll), normal contact 30 of relay RT, normal contact 31 of relay CS to ground at contact 16 of relay SE. The operator seeing the two lamps AL and CL burning will know that the calling subscriber has replaced his receiver, and she will now withdraw th plugs AP and GP to permit the cord circuit to restore to normal.

From the foregoing, it will be readily understood that I have designed a system wherein a call is registered against the calling subscribers line when the called subscriber responds and that only one "call can be registered upon a single connection of the same subscribers. It will be further seen that the system above described contains positive means for immediately disassociating the cord circuit from its connected lines upon the calling party replacing his receiver when the cord circuit C is connected to a trunk line or any line having a low resistance cut-off relay, but when the cord circuit is connected to a local line or to a line having a high resistance cut-oil relay, the disassociation of the calling end of the cord circuit from said line is under the joint control of the calling and called subscribers.

It is to be understood that I do not desire to be limited to the exact arrangement of my invention as illustrated and described, as changes and modifications may readily suggest themselves to those skilled in the art, but I desire to cover such changes and modifications as come within the scope oi": the ap pended claims.

What I claim as new and desire to secure by United States Letters Patent, is:

1. In a telephone system having a local calling telephone line and a local called telephone line, a trunk line, a link circuit having a manual connection terminal at each end thereof for interconnecting said local lines and also for interconnecting one of said local lines as a calling line and said trunk line, called registering means for said calling line operable to register a complete call when the called subscriber responds, link circuit disconnect means including a relay in the answering end controlled by the calling subscriber and a relay in the calling end of said link circuit for disassociating said link circuit and said telephone lines, and means for placing the said relay in the calling end un-' der the control of the calling and called subscribers upon a local connection, said last means operable to place both of said relays under the sole control, of the calling subscriber upon a trunk connection.

2 In a manual telephone system comprising calling subscribers telephone lines, local called subscribers lines and called trunk lines, link circuits provided with manually operated connection terminals for intercon necting said lines, automatic call registering means for said calling lines, means in said link circuit for operating said call registering 'means, said second means responsive only when the called subscriber responds, means in said link circuit for preventing more than one operation of said call registering means upon a single connection of one of said link circuits with a calling line and a called line, link circuit disconnect means ineluding a relay in the answering end controlled by the callingsubscriber and a relay in the calling end of said link circuit for disassociating said link circuit and said telephone lines, for placing the said relay in the calling end under the control of the calling and called subscribers upon a local connection, said last means opcrableto place both of said relays under the sole control of the calling subscriber upon a trunk connection 3. In a telephone system including calling lines and called lines, link circuits for interconnecting the same, an automatic service meter device individual to each of said calling lines for registering completed calls, antomatic means individual to each of said link circuits responsive to the response'of the called subscriber to effect the operation of said service meter device, means individual to each of said link circuits for preventing the registration of more than one call upon a single connection of one of said link circuits and a calling and a called line, link circuit disconnect means including a relay in the answering end and a relay in the calling end of each of said link circuits for disassociating said link circuit and said telephone lines, and means for placing the said relay in the calling end under the control of the calling and called subscriber upon a local connection, said last means operable to place both of said relays under the sole control of the calling subscriber upon a trunk connec-' tion.

4. A telephone system comprising calling lines, local called lines and trunk lines, link circuits for interconnecting said lines, automatic means for registering calls completed between said lines, automatic link disconnect means individual to and for either end of each of said link circuits for disassociating a connected link circuit and said lines, said link disconnect means at either end of said connected link circuit being'under the sole control of the calling subscriber when the link circuit is connected to a trunk line, and

each of said link circuits operable to effect the operation of said call registering means at the calling subscribers line when the called subscriber responds to a call extendedto either a local line or to a trunk line, link disconnect means including a relay in the am swering end and a. relay in the calling end of eachof said link circuits for disassociating said link circuits and said telephone lines, and means for placing the relay in the answering end of a connected link circuit under the control of the calling subscriber, and the said relay in the calling end under the control of the called subscriber upon a local connection, said last means operable to place both of said relays under the sole control of the calling subscriber upon a trunk connection.

6. In a telephone system comprising calling and called local telephone lines and trunk lines link circuits for interconnecting said local lines, and for interconnecting said local lines and said trunk lines, automatic means for said local lines for registering completed calls between calling and called subscribers lines, automatic ringing means for signaling the called subscriber, automatic means individual to each of said link circuits and operable upon the response of the called subscriber to prevent further application of ringing current to the called line and to effect the operation of said automatic call registering means at the calling subscribers line to register the completed call, individual link disconnect means in either end of each of said link circuits and means for placing the link disconnect means in both ends of a link circuit interconnecting a local line and a trunk line under the sole control of the calling subscriber, and for placing the disconnect means in the answering end and the link disconnect means in the calling end of said link circuit under the control of the calling subscriber and called subscriber respectively upon a local connection tosaid link circuit.

7. In a telephone system including local telephone lines and trunk lines. link circuits for interconnecting said local telephone lines and for interconnecting said local lines and said trunk lines, automatic service registen ing means for registering a call completed between a calling subscriber and a called subscriber, and automatic link disconnect means individual to and for either end of each 01": said link circuits, said link disconnect means atboth ends of a connected link circuit controlled by the calling subscriber when the link circuit is connected to one of said trunk lines, said link disconnect means in the calling end of the connected link circuit controlled by both the calling and called subscribers when said link circuit is connected to a called local line.

8. In a telephone system comprising local telephone lines and trunk lines, link circuits for interconnecting the same, automatic means individual to each of said local lines for registering a call at the calling line when the called subscriber responds link disconnect means individual to and for either end of each of said link circuits for disassociating a connected link circuit and telephone lines, and means individual to each of said link circuits operable to place the link disconnect means at the calling end of a link circuit connected to a trunk circuit under the sole control of the calling subscriber, said last means operable when said link circuit is connected to a called local line to place the calling end link disconnect means under the oint control of the calling and called subscribers.

9. In a telephone system comprising local telephone lines and trunk lines link circuits for interconnecting said lines, automatic service means for registering a call at the calling lines when the called subscriber responds, link disconnect means individual to each of said link circuits for disassociating a connected link circuit and calling and called telephone lines means individual. to said. link circuits for placing said link circuit disconnect means at the calling end of a connected link circuit under the sole control of the calling subscriber when said link circuit is connected to a trunk line, said last means operable to place said last link disconnect means under the control of both calling and called subscribers when the link circuit is connected to a local line.

10. In a telephone system including local lines and trunk lines, link circuits for interconnecting said lines automatic disconnect means individual to each of said link circuits and under the sole control of the calling subscriber for freeing the calling line and trunk line from the link circuit interconnecting said calling line and said trunk line said disconnect means being under the control of the calling subscriber to free the calling line and under the joint control of the calling and called subscribers to tree the called line when the said link circuit interconnects two local telephone lines, and automatic means for registering a call at the calling line when the called subscriber responds. I

11. In a telephone system including local telephone lines and trunk lines, link circuits for interconnecting said lines, automatic link disconnect means individual to each end of each of said link circuits for disassociating a link circuit connected to a calling and called line from said calling and called line, the automatic link disconnect means at the answering end of said connected link circuit being controlled by the calling subscriber, the automatic link disconnect means at the calling end of said link circuit connected to a local line controlled jointly by the calling and called subscribers, said last disconnect means controlled by the calling subscriber exclusive of the called subscriber when said link circuit is connected to a trunk line, automatic registering means in.- dividual to said local lines, and means individual to each of said link circuits and operable when the called subscriber responds to ellect the operation of said automatic means at the calling line to register the call against the calling subscriber.

12. In a telephone system including ditferent classes of telephone lines, link circuits for interconnecting the telephone lines of the same classand for interconnecting telephone lines of diflferent classes, automatic means for registering a call at the calling subscribers line when the called subscriber answers, said call registering means operable regardless of Whether the called subscribers line be one of the same class as the calling subscribers line, or of a different class, link disconnect means individualto each end of each of said link circuits for disassociating a connected link circuit from its lines, the automatic means for disassociating the calling end of said link circuit from a called line of the same class' being controlled jointly by the calling and called subscribers, the said last disconnect means controlled by the calling subscriber:

exclusive of said called subscriber When the called line is of a different class, the link disconnect means in the answering end of said link circuit being always under the sole control of the calling subscriber Whether the GEORGE R. EATON. 

